1.1. Field of the Invention
The invention relates generally to ventilation systems for buildings, and in particular, to passive ventilation systems installed at the roof peak or eaves of the building.
1.2. Problems in the Art
It is generally desirable that fresh air be brought into buildings. A variety of ways exist to try to accomplish this goal. Some systems utilize air conditioners, fans, or other electrically or otherwise powered mechanisms. Such systems are costly to purchase, install and maintain. They also represent ongoing costs such as electric or fuel costs operation.
Passive ventilation systems, also widely known, utilize pressure differences or wind-powered rotors or fans to attempt to set up circulation within the building. There are no on-going energy costs. A few examples of such systems are turbine vents, roof louvers, and soffit vents.
While passive systems do provide a generally more economical solution to air ventilation, especially in low cost non-residential buildings, there are certain considerations that are not always satisfactorily addressed by present systems.
Ideally, the system would prevent such things as rain, snow, ice, or direct wind from entering the building. Prevention of entry of such things as dirt, insects, birds and other animals is also desirable.
On the other hand, it is generally true that the bigger the air passages in and out of the building, the better the potential to create beneficial ventilation. Larger air passages tend to involve larger gaps or spaces between structure, and thus more complex and costly structure to keep out the elements, debris, insects and animals.
Moreover, to promote air flow, many passive systems extend significantly above the roof line of the building. This can be unsightly and can provide a profile that is easier to penetrate or less protected than one closer to the roof line. Also, higher profiles can lead to drift loading on roofs in high snow areas.
Still further, many passive systems do rely on wind or pressure driven parts, such as turbines which, because they are moving parts, can get damaged and can malfunction or operate at less than full effectiveness. The more mechanically complex and larger profile devices also are more susceptible to damage when shipped, installed or serviced. Additionally, they generally take up more space in inventory and are more difficult and time-consuming to install.
Many existing products or methods are suited better to specific building structures or ventilation situations, and therefore are not necessarily universal or flexible in their application.